U.S. Pat. No. 4,509,377 dated Apr. 9, 1985, for "Load Testing" shows load testing of a crane where pull is against buliding beams of the building containing the crane. Said U.S. Pat. No. 4,509,377 is incorporated here by reference, for an introduction to load testing, particularly load testing of cranes.
Russian Author's Certificate No. 670,847 shows a test where pull is against a ferromagnetic sheet secured in the ground at a test site. An electromagnet is used for making the connection to the sheet.